This invention relates to a device for shifting without a clutch and without synchronizing elements in a multiple gear ratio transmission of a vehicle drive.
From German Letters of Disclosure 27 42 033 there is known a device for obtaining synchronous operation of a multiple gear ratio transmission whereby, on the shifting of the transmission from one gear into another, a control unit designated as a "regulator" changes the engine rotational speed from a speed corresponding to one gear to a speed corresponding to the other gear following a predefined speed gradient. On reaching the synchronous speed of the engine associated with the new gear, the shifting of the transmission is carried out, possibly with a lead allowance. The change of the engine rotational speed according to the predefined fixed speed gradient implies, however, that a true matching of the engine rotational speed to the synchronous speed corresponding to the new gear is not attained. It follows that, unless shifting is executed precisely on attainment of the synchronous speed, an overshooting of the engine speed occurs so that a new control process must follow. The disclosed device can be best utilized in an arrangement in which the gearshifting is executed automatically, i.e., the attainment of the synchronous speed can be utilized as a signal for the carrying-out of the gearshifting process. However, if the operator actuates the gearshift manually, considerable difficulties are encoutered since the operator, on appearance of a signal indicating the synchronous state, would have to shift immediately. This is not always possible, particularly in case of rough or tight shifts. The known arrangement, furthermore, deals only with the setting of the synchronous speed, and thus assumes a state in which the old gear has already been disengaged. However, nothing is indicated as to how this might be possible and atained without actuation of a clutch.